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SQL Server Backup and Restore to Cloud Simplified

Posted on 24 January, 2013

Editor’s Note: Today’s post was written by Guy Bowerman and Karthika Raman from the Microsoft Data Platform team.

SQL Server 2012 SP1 Cumulative Update 2 includes enhancements to SQL Server native backup that simplifies backup and restore of a SQL Server Database to Window Azure storage. The SQL Server database can be either on an on-premises instance of SQL Server or on an instance of SQL Server running in a hosted environment such as Windows Azure Virtual Machine. Read the information below to get a brief introduction to the new functionality and follow the links for more in-depth information.

To download the update, go to the SQL Release Services Blog.


In addition to disk and tape you can now use SQL Server native backup functionality to back up your SQL Server Database to the Windows Azure Blob storage service.  In this release, backup to Windows Azure Blob storage is supported using T-SQL and SMO.  SQL Server Databases on an on premises instance of SQL Server or in a hosted environment such as an instance of SQL Server running in Windows Azure VMs can take advantage of this functionality.


  • Flexible, reliable, and limitless off-site storage for improved disaster recovery: Storing your backups on Windows Azure Blob service can be a convenient, flexible and easy to access off-site option. Creating off-site storage for your SQL Server backups can be as easy as modifying your existing scripts/jobs. Off-site storage should typically be far enough from the production database location to prevent a single disaster that might impact both the off-site and production database locations. You can also restore the backup to a SQL Server Instance running in a Windows Azure Virtual Machine for disaster recovery of your on-premises database. By choosing to geo replicate the Blob storage you have an extra layer of protection in the event of a disaster that could affect the whole region. In addition, backups are available from anywhere and at any time and can easily be accessed for restores.
  • Backup Archive: The Windows Azure Blob Storage service offers a better alternative to the often used tape option to archive backups. Tape storage might require physical transportation to an off-site facility and measures to protect the media. Storing your backups in Windows Azure Blob Storage provides an instant, highly available and durable archiving option.
  • No overhead of hardware management: There is no overhead of hardware management with Windows Azure storage service. Windows Azure services manage the hardware and provides geo-replication for redundancy and protection against hardware failures.
  • Currently for instances of SQL Server running in a Windows Azure Virtual Machine, backing up to Windows Azure Blob storage services can be done by creating attached disks. However, there is a limit to the number of disks you can attach to a Windows Azure Virtual Machine. This limit is 16 disks for an extra-large instance and fewer for smaller instances. By enabling a direct backup to Windows Azure Blob Storage, you can bypass the 16 disk limit.
  • In addition, the backup file which now is stored in the Windows Azure Blob storage service is directly available to either an on-premises SQL Server or another SQL Server running in a Windows Azure Virtual Machine, without the need for database attach/detach or downloading and attaching the VHD.
  • Cost Benefits: Pay only for the service that is used. Can be cost-effective as an off-site and backup archive option.

The Windows Azure pricing calculator can help estimate your costs.

Storage: Charges are based on the space used and are calculated on a graduated scale and the level of redundancy. For more details, and up-to-date information, see the Data Management section of the Pricing Details article.

Data Transfers: Inbound data transfers to Windows Azure are free. Outbound transfers are charged for the bandwidth use and calculated based on a graduated region-specific scale. For more details, see the Data Transfers section of the Pricing Details article.

How it works:

Backup to Windows Azure Storage is engineered to behave much like a backup device (Disk/Tape).  Using the Microsoft Virtual Backup Device Interface (VDI), Windows Azure Blob storage is coded like a “virtual backup device”, and the URL format used to access the Blob storage is treated as a device.  The main reason for supporting Azure storage as a destination device is to provide a consistent and seamless backup and restore experience, similar to what we have today with disk and tape.

When the Backup or restore process is invoked, and the Windows Azure Blob storage is specified using the URL “device type”, the engine invokes a VDI client process that is part of this feature.  The backup data is sent to the VDI client process, which sends the backup data to Windows Azure Blob storage.

As previously mentioned, the URL is much like a backup device used today, but it is not a physical device, so there are some limitations.  For a full list of the supported options, see SQL Server Backup and Restore with Windows Azure Blob Storage Service.

How to use it

To write a backup to Windows Azure Blob storage you must first create a Windows Azure Storage account, create a SQL Server Credential to store storage account authentication information. By using Transact-SQL or SMO you can issue backup and restore commands.

The following Transact-SQL examples illustrate creating a credential, doing a full database backup and restoring the database from the full database backup. For a complete walkthrough of creating a storage account and performing a simple restore, see Tutorial: Getting Started with SQL Server Backup and Restore to Windows Azure Blob Storage Service.

Create a Credential

The following example creates a credential that stores the Windows Azure Storage authentication information.

Backing up a complete database

The following example backs up the AdventureWorks2012 database to the Windows Azure Blob storage service.

Restoring a database

To restore a full database backup, use the following steps.


Concepts/Script Examples

Best Practices /Troubleshooting

Getting Started Tutorial

Please send your feedback on the feature and or documentation to karaman @ or guybo @